1. Field of the Invention
The present invention relates generally to a manufacturing method of thin heat pipe, and more particularly to a manufacturing method of thin heat pipe, in which the mesh capillary structure is prevented from being deformed due to pressing. Therefore, the thermal conductivity of the heat pipe will not be affected.
2. Description of the Related Art
A heat pipe has heat conductivity several times to several tens times that of copper, aluminum or the like. Therefore, the heat pipe has excellent performance and serves as a cooling component applied to various electronic devices. As to the configuration, the conventional heat pipes can be classified into heat pipes in the form of circular tubes and heat pipes in the form of flat plates. For cooling an electronic component such as a CPU, preferably a flat-plate heat pipe is used in view of easy installation and larger contact area. To catch up the trend toward miniaturization of cooling mechanism, the heat pipe has become thinner and thinner in adaptation to the cooling mechanism.
The heat pipe is formed with an internal space as a flow path for the working fluid contained in the heat pipe. The working fluid is converted between liquid phase and vapor phase through evaporation and condensation and is transferable within the heat pipe for transferring heat. The heat pipe is formed with sealed voids in which the working fluid is contained. The working fluid is phase-changeable and transferable to transfer heat.
The heat pipe is used as a heat conduction member. The heat pipe is fitted through or plug-in connected with a radiating fin assembly. The working fluid with low boiling point is filled in the heat pipe. The working fluid absorbs heat from a heat-generating electronic component (at the evaporation end) and evaporates into vapor. The vapor goes to the radiating fin assembly and transfers the heat to the radiating fin assembly (at the condensation end). A cooling fan then carries away the heat to dissipate the heat generated by the electronic component.
Currently, there are many methods for manufacturing the heat pipes. For example, the heat pipe can be manufactured in such a manner that metal powder is filled into a hollow tubular body and sintered to form a capillary structure layer on the inner wall face of the tubular body. Then the tubular body is vacuumed and filled with the working fluid and then sealed. Alternatively, a mesh capillary structure body is placed into a tubular body and sintered to form a capillary structure layer on the inner wall face of the tubular body. Then the tubular body is vacuumed and filled with the working fluid and then sealed. On the demand of the electronic equipment for slim configuration, the heat pipe must be made with a thin configuration.
Please refer to FIG. 1, which is a sectional view of a thin heat pipe made by means of a conventional thin heat pipe manufacturing method. In the conventional technique, a mesh capillary structure body 12 is placed into a hollow tubular body 11. Then the tubular body 11 is pressed into a flat form. Then the hollow tubular body is 11 vacuumed and filled with the working fluid. Finally, the hollow tubular body 11 is sealed. According to such process, the hollow tubular body 11 can be made with a flat configuration. However, when flattening the hollow tubular body 11, the mesh capillary structure body 12 is not fully attached to the inner wall face of the hollow tubular body 11 or even is detached from the inner wall face along the junction between the mesh capillary structure body 12 and the inner wall face. Accordingly, when flattening the hollow tubular body 11, the mesh capillary structure body 12 is often deformed and cannot be fully tightly attached to the inner wall face of the hollow tubular body 11. In some more serious cases, the mesh capillary structure body 12 will be even detached from the inner wall face. As a result, the hollow tubular body 11 can be hardly completely flattened and the completeness of the vapor-liquid circulation passageways in the heat pipe will be affected. This will lead to deterioration of the thermal conductivity.
According to the above, the conventional technique has the following shortcomings:
1. The mesh capillary structure body is likely to deform.
2. The hollow tubular body can be hardly completely flattened.
3. The completeness of the vapor-liquid circulation passageways in the heat pipe will be affected.
4. The thermal conductivity is deteriorated.